As is known to those skilled in the art to which the present invention pertains, the mounting of exterior accessories, such as mirrors and the like, to vehicular bodies creates certain long-term problems. This is especially true where the body is made of a thin sheet metal or plastic, such as fiberglass or the like. Over extended periods of time there is a tendency for a mirror assembly to “creep” or to become dislodged and move from its original mounting position. This is because, typically, such mirror assemblies are mounted via a mounting bracket which uses threaded fasteners which extend through the sheet metal or through pre-formed holes or apertures formed in the vehicular body. Because of vibration, bouncing, rutting and the like, the hole or aperture tends to expand or deform thus causing the “creep”. The art has sought to alleviate this problem through the use of improved fasteners such as well nuts and the like. However, this has not proved sufficient.